Martian real estate can be broken down into two categories: habitable and open. Habitable real estate is the area under the dome which allows human settlers to live there in a relatively conventional environment. Open real estate, on the other hand, lies outside the domes. Open real estate is far less valuable than habitable real estate; however, both of these areas can be bought and sold, and as transportation costs drop, both forms of Martian real estate will rise in value.
At this present moment, habitable real estate does not exist on Mars; only 144 million square kilometers of open land exist. In order to get the real estate market going, a mechanism should be installed that could enforce private property rights on Mars; land there could then probably be bought and sold now. In order to accomplish and enforce this mechanism the United States would give a patent or property registry. This claim would be enforced internationally by having the U.S. Customs Office penalize with a punitive tariff any U.S. import anywhere, directly or indirectly, with material that was extracted in defiance of the claim.
Once this mechanism has been set in place, the undeveloped open real estate on Mars represents a tremendous source of capital to finance the initial development of Martian settlement. If the land was sold at approximately $10 per acre, Mars would be worth an estimated $358 billion. If Mars is terraformed, these open land prices would increase to a value of $36 trillion!
As is with Earth, all open real estate will not be of equal value. The sections known to contain valuable minerals, water, geothermal power potential, or other resources, or which are located closer to the habitable areas, will be worth much more. Far more valuable than the open real estate will be the habitable real estate beneath the domes. Each 100 meter diameter dome, massing about eighty tons would enclose an area of about two acres. If the figures projected seem to go as planned, the creation of habitable land by mass production and erection of large numbers of domes to house the waves of people could prove to be one of the biggest businesses on Mars, garnering a total of one million dollars per dome.
As the Earth's population grows, real estate will become even more expensive; thus, making it harder for people to own their own homes. Add on politics and the world will be somewhat confined, thus limiting opportunities for all and seeking to enforce cultural norms that will be unacceptable to many. When the frictions turn inevitable a place of refuge will be needed; Mars will be this place of refuge.